Not attacking your opinion at all, I just don't agree. If, in 1940, Hitler had destroyed the allies in Dunkirk, that war would have been over. He didn't invade Russia for another year. After the western powers were done, he could've crushed Russia, they weren't ready at that time. Add to that, there was a pro German sentiment in the USA and we would've stayed isolationist. The thing was, Ribbentrop , Hitlers sec of state, was a great negotiator, just not as shrewd as Stalin. People wonder why he signed the non aggression pact, but if you look at it, it was smart. He figures, hey, if Germany breaks this thing, they're probably already gonna be fighting France and England, so what do I have to lose. He knew he was in no position to oppose Hitler at that point, but didn't expec him to invade until 1943. Fact is, I believe had he crushed the western allies, he could've then turned his sights to russia, and it would've been just in time to beat the winter. Case closed, Germany conquers Europe. Funny though, 70 years later, and they've done just that. 
Every point you made is a valid point and yes would dramatically improve Hitler's situation, but consider the following; the Russians are never defeated, check out their history they simply pick up, retreat and live to fight another day, their land is so vast, no army would dare chase them, also the British and US are in no matter what, the second Hitler hit Poland in 39, The second the western allies are in the game. Now have you read the sun Tzu, well I practically have memorized it and the Germans where breaking every law in the book, and they where severely outnumbered, but more importantly the Nazi's ran out of resources before the war ended, how do you solve that problem, had Hitler never made a mistake, he still ran out of resources, outnumbered 10 to one with no available resource, game over no matter what, plain and simple.
